This invention relates to a semiconductor wafer processing system having a process line formed by a plurality of processing devices, and more particularly to a system where each processing device processes a semiconductor wafer bonded by an adhesive to a ring-shaped frame. The wafer bonded to the frame is referred to as a "workpiece" below.
A conventional semiconductor wafer processing system of this type is shown in FIG. 9. The system includes an automatic semiconductor wafer bonding device 1 with a wafer loader 1a and a frame loader 1b, a dicing device 2, an ultraviolet (UV) ray applying device 3, and a stacker 4. These processing devices 1 through 4 are connected in sequence in the stated order. The system further includes a host computer (not shown) for controlling movement of a wafer bonded to a frame hereinafter referred to as a workpiece W between these processing devices. UV ray applying device 3 subjects workpiece W to UV rays to reduce the adhesive strength between the semiconductor wafer bonded to workpiece W and the special adhesive tape used to bond the wafer to workpiece W. The adhesive tape is designed so that when the adhesive tape is exposed to UV rays, it loses the adhesive strength, thereby facilitating removal of a semiconductor chip out of the wafer in subsequent die bonding processes.
This type of conventional semiconductor wafer processing system suffers from several flaws, in that at times when one of upstream processing devices in the process flow breaks down, or one lot of workpieces is shifted with respect to another lot in automatic wafer bonding device 3, the movement of workpieces in the process line may be suspended. In other words, each downstream processing device will have a waiting time, resulting in low work efficiency.
Further, if any upstream processing device has a smaller processing capacity than a downstream processing device, the work efficiency of the system will be limited to the capacity of the upstream processing device. Upstream processing refers to early stages in the process sequence and downstream processing refers to later stages in the process sequence.
Further, in a conventional semiconductor wafer processing system, the orientation direction of the workpiece placed in the unloader may be different from the orientation direction of the workpiece as originally supplied from the loader, which makes handling of the workpiece difficult in subsequent processing step.
Furthermore, if a particular lot of workpieces is required to be processed out of turn, it would be difficult to allow such a lot to be inserted in the processing line.